Gemstone Spotlight: Coral

Coral
by: Ben Tseytlin - on Antiques & Jewelry

Coral gemstone is distinct from most gemstones because instead of consisting of minerals that use a crystal structure, it is organic in origin, and is formed as the result of biological processes. As such, coral is related to pearls, gems and ivory.

Characteristics

Coral has a structure similar to skeleton which is constructed by miniature marine animals called coral polyps. Gem grade coral is associated with coral that forms in reefs, and the most valuable specimens are located near the coasts of Japan, the Mediterranean or Red Sea. The colors may vary but will range from light to darker red, as well as pink, orange, blue, white and black. Coral that is unworked will appear dull in appearance, but after polishing will display a spectacular vitreous luster.

Coral grows on the bottom of rocky ocean beds in a dark environment. Its structure is comprised of hardened calcium carbonate which gets its color from carotenoid pigments. Its vivid luster and coloration has made it sought after since ancient times, when it was mostly used for decorative purposes. It was harvested in Sardinia and deposits have also been found in Australia and Taiwan.

Shopping For Coral

Because coral is organic, it is not as durable as diamonds, sapphires or rubies. However, it is hard enough to form into jewelry. On Mohs scale it has a hardness rating of 4 (sometimes 3). It has sensitivity to high temperatures as well as acid, and the color might fade slightly as time passes. Jewelers will polish it using sandstone which is finely grained along with emery, and afterwards it can be placed in cabochons, beads or any ornamental object you desire. It has also been used in necklaces.

Coral jewelry is somewhat rare and may be difficult to find in most brick and mortar stores, so you will need to check online. It will add a flash of color to any clothing you’re wearing, whether it is formal or casual. Those attending high society events will look great in coral earrings, a necklace or ring, and for casual occasions, you can wear a coral pendant, bracelet or studs. It is important to choose jewelry that matches your personality and philosophy, and for metal color, coral works best with either yellow gold or rose, and will produce a seamless transition from the gemstone to metal.

How To Care For Coral

Coral can be easily scratched or fractured, so extra care must be taken when wearing or storing it. Use liquid mild soap to clean it, and never use detergents or brushes which are abrasive since they will scratch it. When wet it must be thoroughly dried to prevent waters stains.

Never apply ultrasonic cleaners to your coral, since the vibrations might lead to fracture. When placing coral jewelry in storage, make sure it is placed in a container that is lined with fabric, as this will prevent scratches. It should not be stored in closed proximity to other gems, especially harder ones.